1. Field of the Invention
The present invention relates generally to a suspension such as that used in an automotive vehicle and more specifically to an insulator or bush arrangement therefor which simultaneously provides good rigidity and vibration damping characteristics.
2. Description of the Prior Art
In nearly all suspension arrangements (for example see Nissan Service Weekly Vol. 401 November 1979 page 98), a problem is encountered in that elastomeric bushes interposed between members subject to vibration and a chassis or base which is to be isolated from the vibrations, such as the chassis of an automotive vehicle, are required to simultaneously support large weights (e.g. a vehicle chassis) and absorb relatively high frequency vibration. However, in order to provide the required rigidity and therefore support (viz., resistance to displacement), the insulator is required to be relatively hard. However, in order to absorb relatively high frequency vibration the elastomer used in the insulator should be relatively soft. Accordingly, in view of this conflict it is quite difficult to provide an arrangement which will adequately provide both functions.
One attempt to acheive the required characteristics is disclosed in Nissan Service Weekly issued in June 1980. This arrangement features the provision of a dynamic vibration damping device which is attached to a member of the suspension subject to vibration. This device upon being excited by vibration produces a similar vibration but with a 180 degree phase difference. The vibration produced by the dynamic damper and that which excites same, neutralize each other. This arrangement while proving effective undesirably increases the complexity and weight of the vehicle or device to which it is applied.